From f6f85f475ba2abd186ddda10d0099750e28231ca Mon Sep 17 00:00:00 2001
From: George Rennie <georgerennie@gmail.com>
Date: Sun, 24 Sep 2023 12:40:41 +0100
Subject: [PATCH] smt2: Check for constant bool after fully resolving signal

* This fixes #3769
---
 backends/smt2/smt2.cc | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/backends/smt2/smt2.cc b/backends/smt2/smt2.cc
index 5e63e62370d..703628b7367 100644
--- a/backends/smt2/smt2.cc
+++ b/backends/smt2/smt2.cc
@@ -329,13 +329,14 @@ struct Smt2Worker
 	{
 		sigmap.apply(bit);
 
+		if (bit_driver.count(bit)) {
+			export_cell(bit_driver.at(bit));
+			sigmap.apply(bit);
+		}
+
 		if (bit.wire == nullptr)
 			return bit == RTLIL::State::S1 ? "true" : "false";
 
-		if (bit_driver.count(bit))
-			export_cell(bit_driver.at(bit));
-		sigmap.apply(bit);
-
 		if (fcache.count(bit) == 0) {
 			if (verbose) log("%*s-> external bool: %s\n", 2+2*GetSize(recursive_cells), "",
 					log_signal(bit));